Voltage regulating relay



Dec. 24, 1968 R. J. SULLIVAN VOLTAGE REGULATING RELAY Filed Aug. 26,1966 United States Patent Office 3,418,539 VOLTAGE REGULATING RELAYRobert J. Sullivan, Wayne, N.J., assignor to Westinghouse ElectricCorporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug.26, 1966, Ser. No. 575,396 7 Claims. (Cl. 317-142) This inventionrelates generally to relaying apparatus and more particularly toapparatus which energizes a relay in a timed manner.

An obpect of this invention is to provide a time-actuated self-lockingrelaying apparatus.

A further object of this invention is to provide a time delay apparatuswhich times both the time period that the actuating signal is appliedand the time period that the actuating signal is removed.

Another object is to provide a timing apparatus which will time out in aleser time period than the full time period of the timer when an initialsignal is applied for a lesser time interval than the full timinginterval, the initial signal is interrupted for an interval which isless than the time period that the initial signal is applied, and asignal is thereafter reapplied.

A further obpect is to proivde such an apparatus having an energystorage device which is charged and discharged through impedances ofsubstantially the same magnitude.

Other objects of this invention will be apparent from the description,the hereinafter appended claims and the drawing, the sole figure ofwhich schematically illustrates a voltage controlling network for atransmission line embodying the invention.

Referring to the drawings by characters of reference, the numeral 1indicates generally a transmission line having a local end portion 1A atwhich the voltage and current sampling equipment are located and aremote portion 1B at which a load 2 is located. The apparatus lo catedat line portion 1A provides the load 2 with a regulated substantiallyconstant voltage.

The voltage at the load 2 is sensed at the local end 1A of thetransmission line 1 by combining voltage and current quantities derivedby means of a current transformer 4 and a voltage or potentialtransformer 6. The primary winding 7 of the current transformers 6 andthe primary winding 8 of the transformer 6 are connected to thetransmission line 1 at the local line portion 1A. The secondary winding10 of transformer 6 and the secondary winding 11 of the currenttransformer 4 supply the required voltage and current signals to acompensating network 12 which compensates for the line drop between theportions 1A and 1B.

The compensating network 12 comprises a transformer 14, a transactor ormutual inductor 15, and a resistor network 20, and a variable resistor22. The output electrical quantity of the secondary winding 10, ismodified by the voltage established in the output winding 18 of themutual inductor 15 and in the resistor network whereby the magnitude ofthe quantity supplied to the primary winding 16 of the transformer 14 isequal to the voltage at the local line portion 1A minus the voltage dropin the transmission line 1 between the local end portion 1A and theremote portion 1B.

The secondary winding 11 of the current transformer 4 is connectedacross the primary winding 26 of the mutual inductor 15 through aportion of the resistor network 20 whereby the output quantity of theseries connected transactor 15 and resistor network 20 decreases theoutput voltage of the winding 10 by an amount which is electricallyequivalent in phase and magnitude to the voltage drop between the localportion 1A and the remote portion 1B of the transmission line 1.

3,418,539 Patented Dec. 24, 1968 The secondary winding 28 of thetransformer 14 is connected across the alternating current inputterminals 30 of a fullwave rectifying bridge network 32 through acurrent limiting resistor 34. The direct current output terminals 36 ofthe network 32 are connected to input terminals 38 and 40 of a bridgenetwork 42 through a filter network 43 to energize the network 42 withan electrical quantity having a magnitude which is a direct function ofthe potential at the load 2.

The filter network 43 may take any of a number of forms. Preferably, ittakes the form, as illustrated, in which a first filter capacitor 44 isconnected between the output terminals 36 of the rectifier network 32, asecond filter capacitor 45 is connected directly between the bridgenetwork terminals 38 and 40 and resistors 46 and 47 are connected inparallel with each other between one of the rectifier network terminals36 and the bridge terminal 38. A thermistor 48 is connected in serieswith the resistor 47 to compensate the network for temperature changes.

The bridge network 42 comprises two parallel arms interconnecting theterminals 38 and 40. The first of these arms includes, in seriesconnection, a resistor 50, the resistive element of a potentiometer 52and a resistor 54. The other arm includes a resistor 59 and a Zenerdiode 58. The bridge network 42 further is provided with a pair ofoutput terminals 60 and 62; the terminal 60 being connected to themovable arm 63 of the potentiometer 52 and the output terminal 62 beingthe common connection of the resistor 56 and the Zener diode 58.

The magnitude of the breakover voltage of the Zener diode 58 and themagnitudes of the resistance of the re sistor 50, 54 and 56, theresistor element of the potentiometer 52 and the adjustment of themovable arm 63 on the resistor element of the potentiometer 52 areselected so that when the voltage supplied to the load 2 is within theselected bandwidth, the magnitude of the electrical quantity appliedacross the input terminals 38 and 40 of the bridge network will maintainthe output terminals 60 and 62 at substantially the same potential. Ifthe potential at the load 2 exceeds this desired voltage bandwidth, thepotential between the input terminals 38- and 40 will increase and thepotential of the terminal 60 will elevate above that of the potential ofthe output terminal 62. The opposite effect on the potential between theoutput terminals 60 and 62 occurs when the voltage supplied to the load2 decreases below the desired voltage bandwidth. A suitable bandwidth is:1 volt from the desired voltage.

Any form of amplifier responsive to the direction of flow of an inputquantity applied thereto and having a suitable output quantity foroperating a suitable voltage raising or voltage lowering mechanism(illustrated by labeled VOLTAGE RAISE DEVICE and VOLTAGE LOWER DEVICE)may be connected to the output terminals 60 and 62 of the bridge network42. A preferred form of such amplifier is as illustrated and comprises apair of magnetic amplifiers 64 and 66.

The magnetic amplifiers 64 and 66 include saturable cores 68-A68B and70A70B respectively. Each core is preferably of a material having asubstantially rectangular hysteresis loop (two cores each). The set 68of two cores 68A and 68B is provided with a control winding 72 and abias winding 74 both of which are wound over both cores 68A and 68B.Similarly, set 70 of cores 70A and 70B is provided with a controlwinding 76 and a bias winding 78 both of which are wound over both cores70A and 703. The gate winding of the magnetic amplifier 64 comprises apair of winding portions 80A and 80B which are individually located onthe cores 68A and 68B respectively. Likewise, the gate windings of themagnetic amplifier 66 comprises winding portions 82A and 82B which areindividually located on the cores 70A and 70B.

The magnetic amplifiers 64 and 66 are energized respectively from thecenter-tapped secondary windings 84 and 86 of a transformer 88 havingits primary winding 90'energized from a suitable source of alternatingcurrent potential which may be, as illustrated, the secondary winding ofthe transformer 6. The center tap of the winding 84 is connected to themovable contact of a resistor 92 which connects the two correspondingterminals of the winding portions A and 80B. Similarly, the center-tapconnection of the winding 86 is connected to the movable contact of aresistor 94 which connects corresponding terminals of the windingportions 82A and 82B. The dotted terminals of the winding portions 80Aand 80B are connected to the end terminals of the winding 84 andsimilarly the dotted terminals of the gate winding portion 82A and 82Bare connected to the end terminals of the secondary winding 86.

The transformer 88 is provided with an additional secondary winding 96which supplies power for the relaying networks 110R and 110L and for thebias windings 74 and 78. The end terminals of the winding 96 areconnected to the alternating current input terminals 97 of a full-wavebridge rectifier 98. The positive direct current output terminal 99 ofthe network 98 is connected through a resistor 100 to a positive directcurrent bus 102. The negative output terminal 103 of the full-wavebridge 98 is connected directly to the negative bus 104. The voltagebetween the buses 102 and 104 is controlled by means of a Zener diode105 connected in series with a pair of diodes 106 and 107 between thepositive bus 102 and the negative bus 104. The output of the rectifierbridge 98 is smoothed by a filter capacitor 108 connected between itsdirect current output terminals 99 and 103.

The magnetic amplifiers 64 and 66 are individually provided with outputbusses 64A and 66A. The potentials which exist between the negative bus104 and the output busses 64A and 66A are the output quantities of theamplifiers 64 and 66 respectively. The bus 64A is connected through apair of oppositely poled diodes to the opposite ends of the resistor 92and through a diode 112R to one terminal 113R of a capacitor 114R.Similarly, the bus 66A is connected through oppositely poled diodes tothe ends of the resistor 94 and through a diode 112L to one terminal113L of a capacitor 114L. The opposite terminals of the capacitors 114Rand 114L are connected to the bus 104, which is connected to theadjustable taps of the resistors 92 and 94. Preferably, the busses 64Aand 66A are prevented 'from becoming appreciably negative with respectto the bus 104 by diodes 115R and 115L. Resistors 116R and 116L may beused to limit the positive excusions of the busses 64A and 66A.

The bias winding 74 and 78 of the magnetic amplifiers 64 and 66 areconnected in series between the direct current bus 104 and an adjustabletap 117 of a voltage divider 118 connected between the buses 102 and104. The adjustment of the tap 117 and the consequent magnitude ofcurrent through the bias windings 74 and 78 determines the voltagebandwidth established at the load 2. The control windings 72 and 76 areconnected in series between the output terminals 60 and 62 of the bridgenetwork 42 which controls the direction and magnitude of current throughthese windings 72 and 76. The windings 72, 74, 76, 78, 80A, 80B, 82A and82B are polarized with respect to each other such that when currentflows through the control windings 72 and 76 as a consequence of thepotential of terminal 62 being positive with respect to that of terminal60, the bus 64A be energized and the bus 66A remain deenergized andconversely when the potential of terminal 60 is positive with respect toterminal 62.

The relay operating networks 110R and 110L are identical and the samereference characters will be used for like elements in each thereof. Inthe specification, in certain instances for clarity, the sufiix R or Lwill be added to the numerals to make it clear which of the networks110R or 110L is being referred to.

Each network 110 includes an energy storage device which may take theform of a capacitor 122 having one of its terminals connected to thenegative bus 104 and its other terminal 123 connected through resistors124, 126 and 128 to the positive bus 102. The timing interval of thenetwork 110 is determined primarily by the magnitude of the resistanceof the resistor 126 which controls the rate at which charging currentflows to and flows from the capacitor 122. To control these intervals,the common terminal 130 of the resistors 126 and 128 is connected to thenegative bus 104 through the emitter cathode circuit of a transistor132. The base of transistor 132 is connected to the common terminal 133the resistors 134 and 136 of a voltage dividing network comprising theresistors 134, 136 and 138. The terminal 133 is normally positive withrespect to the negative bus 104 whereby base current normally fiowsthrough the base emitter circuit of the transistor 132 and maintains thetransistor 132 conducting to prevent the flow of charging current to thecapacitor 122. Conducting of transistor 132 also completes a timecontrolled discharge circuit for the capacitor 122 through the resistors124 and 126, and will hold the capacitor 122 in substantially completelydischarged conditions thereafter.

The voltage dividing networks 134, 136 and 138 is provided with a secondoutput terminal 140 which is located intermediate the resistors 136 and138. The terminal 140 is selectively connected through theemittercollector circuit of the transistor 120 to the negative bus 104.When the voltage supplied to the load 2 is of the desired magnitude, themagnetic amplifiers 64 and 66 have no output potential, the capacitors114 are discharged and no base current will flow from either of theterminals 113R or 113L through the current limiting resistors 119 and tothe transistor 120. With transistor 120 in its non-conducting state, thepotential of the terminal 133 is maintained elevated with respect to thebus 104 and base current flows in the transistor 132. The resultingemitter-collector conduction of transistor 132 prevents the flow ofcharging current to the capacitor 122. If the capacitor 122 is partiallycharged at the time the transistor 132 is rendered conducting, anypartial charge therein discharges through the resistor 126. When thepotential supplied to the load 2 is below or above the desired potentialbandwidth, the magnitude amplifiers 64 or 66 render one or the other ofthe transistors 120R and 120L, as the case may be, conducting therebyrendering one or the other of the normally conducting transistors 132Ror 132L blocked to permit charging current to flow to the one of theother of the capacitors 122R or 122L.

The potential appearing across the capacitor 122 is applied between theemitter and the base b of a voltage sensitive switch 142 whichpreferably is, and is illustrated as being, a unijunction transistor.The base b of the unijunction transistor 42 is connected to the positivebus 102 through a resistor 143, the base [1 is connected to bus 104through the energizing winding of a magnetic rlezlgy 144, and theemitter e is connected to the terminal The relay 144 is shown as havingnormally open contacts 145 and normally open contacts 146. A diode 147may be connected in shunt with the energizing winding of the relay 144to pass reactive current. The emitter of the unijunction transistor isconnected through a diode 149, the back contacts 146 and resistor 150 tothe positive bus 102. If desired, the common connection 152 of theresistors 124 and 126 may be connected through a diode 154 to the commonconnection 156 of the back contact 146 and resistor 150. Also, thecommon connection 130 may be connected through a diode 158 to the commoncoinection 159 of the diode 158 and the back contacts 14 It is believedthat the remainder of the details of construction may best be understoodby reference to the operation hereof which is as follows:

Assuming an instant in which the voltage supplied to the load 2 iswithin the desired bandwidth, the potential across the bridge terminals38 and 40 will cause the output terminals 60 and 62 to be atsubstantially the same potentials and not enough current will flowthrough the control windings 72. and 76 to actuate the amplifiers 64 and66.

With the magnitude of current through the control windings 72 and 76below a desired minimum value and the bias windings 74 and 78 energized,as described, the potential of the output buses 64A and 66A of themagnetic amplifiers 64 and 66 will be substantially that of the negativebus 104. Under these conditions neither of the transistors 120R nor 120Lreceives base drive and the transistor 132R and 132L conduct to preventthe flow of charging current to the capacitors 122R and 122L. The chargeon the capacitor 122 will be less than the critical charge required tofire the unijunction transistors 142, the transistors 142 will notconduct to energize the corresponding relay 144 and neither the voltageraise nor the voltage lower devices will be actuated.

Assuming that the voltage applied to the load 2 decreases to a valuebelow the bandwidth value, the potential betwen the terminals 38 and 40of the bridge network 42 will decrease and the potential of the terminal62 will become greater than that of the terminal 60. Under theseconditions, control current flows through the windings 72 and 76 in adirection such that the winding 76 establishes flux which aids thatprovided by the bias winding 78. The magnetic amplifier 66 remains inits off condition.

The direction of this current flow is such that the control winding 72establishes flux which opposes that established by the bias winding 74by an amount sufficient to cause the magnetic amplifier 64 to becomeeffective to energize its output bus 64A. Energization of the bus 64Acauses the capacitor 114R to charge and elevate its terminal 113R, thetransistor 120R is rendered conductive to terminate base current fiow toand thereby terminate conduction of the transistor 132R. When transistor132R becomes nonconducting, charging current flows to the capacitor 122Rat a rate determined primarily by the magnitude of the resistance of theresistor 126.

If this low voltage condition at the load 2 continues withoutinterruption for the timing period of the timer 110R, the voltage acrossthe capacitor 122R rises to a critical value and the unijunctiontransistor 142R conducts. Conduction of the transistor 142R energizesthe relay 144R which thereupon closes its front and back contacts 145Rand 146R.

Closure of the front contacts 145R energizes the voltage raise devicewhereby the voltage supplied to the line 1 is increased throughapparatus (not shown) well known to those skilled in the art. Theclosure of the back coni tacts 146R establishes a holding circuit forthe relay 144R which extends from the positive bus 102 through resistor150R, the now closed back contact 146R, diode 149R to the emitter of theunijunction transistor 142R. This ensures that once the relay has beenenergized it will remain energized until deenergized from a suitableexternal source.

When the voltage at the load 2 is again within the selected bandwidth,the output bus 64A of the magnetic amplifier 64 will no longer beenergized, the capacitor 114R will quickly discharge and the transistor120R will revert to its blocked condition. The transistor 132R revertsto its conducting condition and completes a circuit through the diode158 which effectively interrupts the current flow through the diode 149resulting in the discharge of the capacitor 122 through diodes 154 and158. This decreases the potential of the emitter e of the unijunctiontransistor 142R and it becomes non-conducting. The relay 144R opens itscontacts 145R and 146R whereupon the network 110R reverts to its initialstate and the voltage raise device terminates any further increase involt age of the line 1.

Now assume a condition in which the time interval during which thepotential supplied to the load 2 was below the selected bandwidth for atime period less than the critical timing period of the raise network110R. The re turn of the voltage within the bandwidth causes thetransistor 120R to block and the transistor 132R to reconduct. Whentransistor 132R reconducts, the charge which accumulated in thecapacitor 122R during the blocked period of the transistor 132Rdischarges at a rate determined primarily by the magnitude of theresistor 126R through the emitter collector circuit of the transistor132R. If the voltage supplied to the load 2 remains within the desiredbandwidth for a suflicient time interval, the charge on the capacitor122R will completely or substantially completely drain away through thetransistor 132R and the timer will be reset to time out its maximum timeinterval.

If, however, prior to the complete discharge of the capacitor 122R thevoltage at the load 2 again decreases to a magnitude below the desiredbandwidth, the transistor 120R will again be rendered conducting andblock the transistor 132R. This interrupts the flow of discharge currentand initiates the flow of charging current from and to the capacitor122R through the resistor 126R. Since a partial charge remained in thecapacitor 122R, the time required for the capacitor 122R to reach itscritical value and fire the unijunction transistor 132 will be less thanthe full timing operation of the network 110R. The magnitude of thisreduced timing interval will depend upon the length of the period thatthe voltage at the load 2 was initially below the desired bandwidth.

Preferably the current required to operate the relay 144 is ofsufiicient magnitude so that when the unijunction transistor 142conducts and the winding of the relay 144R is energized, the addedcurrent flow through the resistor reduces the current flow through theZener diode and the diodes 106 and 107. This results in a lesser voltage drop across the diodes 105-107 and results in a decrease in thevoltage applied between the buses 102 and 104. The current through thebias controlling windings 74 and 78 is a direct function of the busvoltage and the decrease in bus voltage reduces the bias current topermit the amplifier to energize its output bus at a lesser magnitude ofvoltage change at the load 2. This eliminates hunting 11 and ensures apositive actuation of one of the relays 144 which are actuated.

If the voltage at the load 2 increases above the bandwidth voltage, themagnetic amplifier 64 will not energize its output bus 64A since theflux caused by the current flow through the windings 72 will aid thatproduced by the winding 74 to the direction which occurred when thevoltage at the load 2 was below the bandwidth level. However, the fluxproduced by the control winding 76 will be in opposition to thatproduced by the bias winding 78 and the amplifier 66 will energize itsoutput bus 66A and the network L will be actuated at the end of thetiming period. The lower relay network 110L operates exactly in the samemanner as described in connection with the raise relaying network 110Rand a further detailed description is not believed necessary.

The voltage regulating apparatus may be tested by the expedient ofinserting desired portions of the resistance 22. This in effectdecreases the voltage applied to the transformer 14 which provides thesame effect as a decrease at the load 2. The magnitude of this decreasemay be observed by the voltmeter 160. Any change in the voltage producedby the change in the setting of resistor 22 should be compensated for bythe voltage controlling network 110 to return the voltage measured bythe voltmeter 160 substantially to its initial reading.

Since numerous changes may be made in the abovedescribed apparatus anddifferent embodiments of the invention may be made without departingfrom the spirit thereof, it is intended that all matter contained in theforegoing description or shown in the accompanying drawings, shall beinterpreted as illustrative and not in a limiting sense.

What is claimed and is desired to be secured by US. Letters Patent is asfollows:

1. In a relaying apparatus, a relay having a current consuming controlelement and circuit controlling means, a pair of electrical energy inputterminals, a pair of buses, a plurality of impedance elements, a Zenerdiode, first circuit means connecting said Zener diode between saidbuses, second circuit means including a first of said impedance elementsconnecting said buses to said input terminals, an energy storageelement, a unijunction transistor having first and second bases and anemitter, third circuit means connecting said bases between said buses,fourth circuit means connecting said storage element in series with asecond of said impedance elements between said buses, fifth circuitmeans connecting said emitter to said fourth circuit means at a locationintermediate said storage element and said second impedance element, aswitching means, sixth circuit means connecting said switching means inshunt with said storage element and said second impedance element, and aseventh circuit means connecting said emitter to one of said buses andincluding said circuit controlling means.

2. The combination of claim 1 in which said fourth circuit meansincludes a third of said impedance elements connected in series withsaid second impedance element intermediate said second impedance elementand said one bus, said sixth circuit being connected between the otherof said buses and a point in said fourth circuit means intermediate saidsecond and third impedance means.

3. The combination of claim 2 in which there is provided an eighthcircuit connecting said emitter to said other bus, said eighth circuitincluding said switching means.

4. The combination of claim 2 in which there is provided a magneticcontrol device having a bias flux setting winding and a control windingand an output winding, means connecting said .bias winding between saidbuses for energization with a current proportional to the voltagebetween said buses, and means connecting said output winding to saidswitching means for actuation of said switching means by said outputwinding, and control means connected to said control winding forenergization of said control winding, said control means being effectiveto energize said control winding to produce flux in said magnetic devicein a direction opposite to that of the flux produced by said biaswinding.

5. A timing network for a relay comprising a relay having a controlelement and circuit controlling means, first and second energy supplyingbuses, an energy storage element, at least one impedance element, aplurality of unidirectional current conducting devices, a voltagesensitive switch having a first and second and third terminals, saidswitch being characterized by the fact that it becomes conductive solelywhen the potential between its said third terminal and its said firstterminal is above a predetermined critical percentage of the potentialbetween its said first and its said second terminals, a first circuitconnecting said first and second terminals to said first and secondbuses respectively, a second circuit connecting said storage element anda first of said impedance elements in series between said buses, saidstorage element being located intermediate said first impedance elementand said first bus, a third circuit connecting said third terminal tosaid second bus and including a first of said unidirectional devices andsaid circuit controlling means, switch means connected in shunt withsaid storage element and said first impedance element, and a fourthcircuit connecting said third terminal to a point in said second circuitwhich is intermediate said storage element and said first impedanceelement, said control element being connected to be energized inresponse to conduction through said first terminal.

6. The combination of claim 5 in which said voltage sensitive switch isa unijunction transistor, said third terminal is said emitter of saidtransistor, said control element is in series circuit with said emitter.

7. The combination of claim 6 in which said second circuit includes asecond of said impedance elements connected intermediate said firstimpedance element and said second bus, said switch means being atransistor.

References Cited UNITED STATES PATENTS 3,277,348 10/1966 Trush 317-1423,303,390 2/1967 Sonnemann 317-36 3,312,865 4/1967 Gambale 317-27 LEE T.HIX, Primary Examiner.

I. A. SILVERMAN, Assistant Examiner.

U.S. Cl. X.R. 31731, 148, 148.5

1. IN A RELAYING APPARATUS, A RELAY HAVING A CURRENT CONSUMING CONTROL ELEMENT AND CIRCUIT CONTROLLING MEANS, A PAIR OF ELECTRICAL ENERGY INPUT TERMINALS, A PAIR OF BUSES, A PLURALITY OF IMPEDANCE ELEMENTS, A ZENER DIODE, FIRST CIRCUIT MEANS CONNECTING SAID ZENER DIODE BETWEEN SAID BUSES, SECOND CIRCUIT MEANS INCLUDING A FIRST OF SAID IMPEDANCE ELEMENTS CONNECTING SAID BUSES TO SAID INPUT TERMINALS, AN ENERGY STORAGE ELEMENT, A UNIJUNCTION TRANSISTOR HAVING FIRST AND SECOND BASES AND AN EMITTER, THIRD CIRCUIT MEANS CONNECTING SAID BASES BETWEEN SAID BUSES, FOURTH CIRCUIT MEANS CONNECTING SAID STORAGE ELEMENT IN SERIES WITH SECOND OF SAID IMPEDANCE ELEMENTS BETWEEN SAID BUSES, FIFTH CIRCUIT MEANS CONNECTING SAID EMITTER TO SAID FOURTH CIRCUIT MEANS AT A LOCATION INTERMEDIATE SAID STORAGE ELEMENT AND SAID SECOND IMPEDANCE ELEMENT, A SWITCHING MEANS, SIXTH CIRCUIT MEANS CONNECTING SAID SWITCHING MEANS IN SHUNT WITH SAID STORAGE ELEMENT AND SAID SECOND IMPEDANCE ELEMENT, AND A SEVENTH CIRCUIT MEANS CONNECTING SAID EMITTER TO ONE OF SAID BUSES AND INCLUDING SAID CIRCUIT CONTROLLING MEANS. 